Systems and methods for a split exhaust engine system

Patent metadata

Field	Value
Publication number	US-11156176-B2
Application number	US-201615382485-A
Country	US
Kind code	B2
Filing date	Dec 16, 2016
Priority date	Dec 16, 2016
Publication date	Oct 26, 2021
Grant date	Oct 26, 2021

Abstract

Methods and systems are provided for operating a split exhaust engine system that provides blowthrough air and exhaust gas recirculation to an intake passage via a first exhaust manifold and exhaust gas to an exhaust passage via a second exhaust manifold. In one example, a method may include supplying air to an exhaust system at a location downstream of an emissions control device via the first exhaust manifold, the air not having participated in combustion in the engine, the first exhaust manifold in fluidic communication with a first exhaust valve of a cylinder and an intake manifold, the cylinder including a second exhaust valve in fluidic communication with the second exhaust manifold. The method may further include adjusting an amount of fuel injected to the engine in response to output of a first oxygen sensor, the first oxygen sensor positioned in the exhaust system upstream of the emissions control device.

First claim

The invention claimed is:

1. An engine control method, comprising:
delivering exhaust combustion gases to an exhaust manifold upstream of a scavenge manifold bypass valve via a first group of cylinder exhaust ports that are directly coupled to the exhaust manifold and in fluidic communication with a plurality of cylinders;
opening the scavenge manifold bypass valve and adjusting air supplied to an exhaust system at a location downstream of an emissions control device via the exhaust manifold in response to a request to regenerate a particulate filter, the air not having participated in combustion in an engine, the exhaust manifold in fluidic communication with a first exhaust valve of a first cylinder, a first exhaust valve of a second cylinder, and an intake manifold, the first cylinder including a second exhaust valve in fluidic communication with an exhaust blowdown manifold, the exhaust blowdown manifold in fluidic communication with a second group of exhaust ports that are in fluidic communication with the plurality of cylinders; and
adjusting an amount of fuel injected to the engine in response to output of a first oxygen sensor, the first oxygen sensor positioned in the exhaust system upstream of the emissions control device.

2. The method of claim 1 , further comprising adjusting the amount of fuel injected to the engine in further response to output of a second oxygen sensor positioned downstream of the emissions control device in a first mode and a second mode, output of the second oxygen sensor modified via a first proportional/integral controller in the first mode, output of the second oxygen sensor modified via a second proportional/integral controller in the second mode.

3. The method of claim 1 , where the particulate filter is located in the exhaust system downstream of the emissions control device and downstream of the location air is supplied to the exhaust system, and further comprising:
adjusting the air via a controller in response to output of a second oxygen sensor located in the exhaust system downstream of the emissions control device.

4. The method of claim 3 , where adjusting the air includes adjusting engine boost pressure.

5. The method of claim 3 , where adjusting the air includes adjusting an amount of intake valve and exhaust valve overlap.

6. The method of claim 1 , where adjusting the air includes adjusting a position of a valve located in a hot pipe positioned between the intake manifold and the exhaust manifold.

7. The method of claim 1 , where adjusting the air includes adjusting a position of a valve located in a scavenge manifold bypass pipe positioned between the exhaust manifold and a location in the exhaust system receiving the air.

8. The method of claim 1 , where an amount of air is supplied in response to engine air flow greater than a threshold, and further comprising:
richening an air-fuel ratio of the engine rich of a stoichiometric mixture and supplying the air to the exhaust system before exhaust gases produced via the richened air-fuel ratio reach the location downstream of the emissions control device; and
ceasing to supply the air to the exhaust system before leaning the air-fuel ratio.

9. An engine control method, comprising:
in a first mode, opening a scavenge manifold bypass valve in response to a request to regenerate a particulate filter and supplying an amount of air to an exhaust system at a location downstream of an emissions control device via a scavenge manifold, the amount of air supplied adjusted in response to output of an oxygen sensor, the scavenge manifold in fluidic communication with a first exhaust valve of a cylinder and an intake manifold, the cylinder including a second exhaust valve in fluidic communication with a blowdown manifold; and
in a second mode, closing the scavenge manifold bypass valve in response to engine air flow less than a threshold and adjusting an amount of fuel injected to an engine in response to output of the oxygen sensor without supplying air to the exhaust system.

10. The method of claim 9 , where the scavenge manifold is an exhaust manifold that is directly coupled to a plurality of exhaust ports, each of the plurality of exhaust ports extending between a cylinder and the scavenge manifold, and further comprising adjusting the amount of air via a turbocharger waste gate.

11. The method of claim 9 , further comprising adjusting the amount of air via adjusting a position of a valve and adjusting an amount of fuel injected in response to a second oxygen sensor positioned downstream of an emissions control device in the first mode and the second mode, output of the second oxygen sensor modified via a first proportional/integral controller in the first mode, output of the second oxygen sensor modified via a second proportional/integral controller in the second mode.

12. The method of claim 9 , further comprising adjusting the amount of air via intake valve and exhaust valve timing actuators.

13. The method of claim 9 , further comprising regenerating an exhaust emissions device via supplying the amount of air to the exhaust system.

14. The method of claim 9 , further comprising supplying engine exhaust to the exhaust system and combining the engine exhaust with the amount of air to provide a stoichiometric mixture.

15. A system, comprising:
an engine including an intake manifold, an exhaust blowdown exhaust manifold, an exhaust manifold, a first group of exhaust ports coupling a plurality of engine cylinders to the exhaust manifold, exhaust ports in the first group of exhaust ports individually coupled to the exhaust manifold, a second group of exhaust ports coupling the plurality of engine cylinders to the exhaust blowdown exhaust manifold, and a compressor;
an exhaust system coupled to the engine, the exhaust system including a first emissions control device and a second emissions control device, the second emissions control device located downstream of the first emissions control device, a first oxygen sensor positioned in the exhaust system upstream of the first emissions control device, a second oxygen sensor positioned in the exhaust system downstream of the first emissions control device and upstream of the second emissions control device;
a scavenge manifold bypass pipe coupling the exhaust manifold to the exhaust system at a location between the first emissions control device and the second emissions control device;
a hot pipe coupling the intake manifold to the exhaust manifold;
an exhaust gas recirculation passage coupling the intake manifold at a location upstream of the compressor to the exhaust manifold; and
a controller operatively coupled to the engine including executable instructions stored in non-transitory memory to flow exhaust gas and air through the exhaust manifold and adjust an amount of fuel injected to the engine in response to output of the second oxygen sensor in a first mode and a second mode, output of the second oxygen sensor modified via a first proportional/integral controller in the first mode, output of the second oxygen sensor modified via a second proportional/integral controller in the second mode.

16. The system of claim 15 , further comprising executable instructions stored in non-transitory memory of the controller to supply air to the exhaust system at a location downstream of the first emissions control device and upstream of the second emissions control device via the exhaust manifold and the scavenge manifold bypass pipe via opening a scavenge manifold bypass valve in response to a request to regenerate a particulate filter.

17. The sys

Assignees

• Ford Global Tech Llc

Inventors

• Ulrey Joseph Norman
• Lewis Donald

Classifications

• F02D41/1446

  the characteristics being exhaust temperatures · CPC title

• F02D41/0007

  for control of turbo-charged or super-charged engines (control of the pumps per se F02B37/12) · CPC title

• F01N3/10 Primary

  by thermal or catalytic conversion of noxious components of exhaust · CPC title

• F02D13/0257

  Independent control of two or more intake or exhaust valves respectively, i.e. one of two intake valves remains closed or is opened partially while the other is fully opened · CPC title

• F02D13/0261

  Controlling the valve overlap · CPC title